From 8dd317313b917f016c90c68f10b78777c0579749 Mon Sep 17 00:00:00 2001
From: Mike Griese <migrie@microsoft.com>
Date: Mon, 11 Oct 2021 10:51:47 -0500
Subject: [PATCH] Clear out `state.json` when we find and empty `settings.json`
 (#11448)

If we find that the settings file doesn't exist, or is empty, then let's quick
delete the state file as well. If the user does have a state file, and not a
settings, then they probably tried to reset their settings. It might have data
in it that was only relevant for a previous iteration of the settings file. If
we don't, we'll load the old state and ignore all dynamic profiles (for
example)!

We'll remove all of the data in the `ApplicationState` object and reset it to
the defaults.

This will delete the state file!

That's the sure-fire way to make sure the data doesn't come back. If we leave
it untouched, then when we go to write the file back out, we'll first re-read
it's contents and try to overlay our new state. However, nullopts won't remove
keys from the JSON, so we'll end up with the original state in the file.

* [x] Closes #11119
* [x] Tested on a cold launch of the Terminal with an existing `state.json`
and an empty `settings.json`
* [x] Tested a hot-reload of deleting the `settings.json`
---
 .../ApplicationState.cpp                      | 20 +++++++++++++++++++
 .../TerminalSettingsModel/ApplicationState.h  |  1 +
 .../ApplicationState.idl                      |  1 +
 .../CascadiaSettingsSerialization.cpp         | 12 +++++++++++
 4 files changed, 34 insertions(+)

diff --git a/src/cascadia/TerminalSettingsModel/ApplicationState.cpp b/src/cascadia/TerminalSettingsModel/ApplicationState.cpp
index acd876884..7e5bc1da3 100644
--- a/src/cascadia/TerminalSettingsModel/ApplicationState.cpp
+++ b/src/cascadia/TerminalSettingsModel/ApplicationState.cpp
@@ -141,6 +141,26 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
     MTSM_APPLICATION_STATE_FIELDS(MTSM_APPLICATION_STATE_GEN)
 #undef MTSM_APPLICATION_STATE_GEN
 
+    // Method Description:
+    // - See GH#11119. Removes all of the data in this ApplicationState object
+    //   and resets it to the defaults. This will delete the state file! That's
+    //   the sure-fire way to make sure the data doesn't come back. If we leave
+    //   it untouched, then when we go to write the file back out, we'll first
+    //   re-read it's contents and try to overlay our new state. However,
+    //   nullopts won't remove keys from the JSON, so we'll end up with the
+    //   original state in the file.
+    // Arguments:
+    // - <none>
+    // Return Value:
+    // - <none>
+    void ApplicationState::Reset() noexcept
+    try
+    {
+        LOG_LAST_ERROR_IF(!DeleteFile(_path.c_str()));
+        *_state.lock() = {};
+    }
+    CATCH_LOG()
+
     Json::Value ApplicationState::_getRoot(const locked_hfile& file) const noexcept
     {
         Json::Value root;
diff --git a/src/cascadia/TerminalSettingsModel/ApplicationState.h b/src/cascadia/TerminalSettingsModel/ApplicationState.h
index 9b4f40f28..d6d2d1749 100644
--- a/src/cascadia/TerminalSettingsModel/ApplicationState.h
+++ b/src/cascadia/TerminalSettingsModel/ApplicationState.h
@@ -53,6 +53,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
 
         // Methods
         void Reload() const noexcept;
+        void Reset() noexcept;
 
         // General getters/setters
         winrt::hstring FilePath() const noexcept;
diff --git a/src/cascadia/TerminalSettingsModel/ApplicationState.idl b/src/cascadia/TerminalSettingsModel/ApplicationState.idl
index 390782683..7890b58c6 100644
--- a/src/cascadia/TerminalSettingsModel/ApplicationState.idl
+++ b/src/cascadia/TerminalSettingsModel/ApplicationState.idl
@@ -28,6 +28,7 @@ namespace Microsoft.Terminal.Settings.Model
         static ApplicationState SharedInstance();
 
         void Reload();
+        void Reset();
 
         String FilePath { get; };
 
diff --git a/src/cascadia/TerminalSettingsModel/CascadiaSettingsSerialization.cpp b/src/cascadia/TerminalSettingsModel/CascadiaSettingsSerialization.cpp
index c0e925c56..83f0952c2 100644
--- a/src/cascadia/TerminalSettingsModel/CascadiaSettingsSerialization.cpp
+++ b/src/cascadia/TerminalSettingsModel/CascadiaSettingsSerialization.cpp
@@ -650,6 +650,18 @@ try
 {
     const auto settingsString = ReadUTF8FileIfExists(_settingsPath()).value_or(std::string{});
     const auto firstTimeSetup = settingsString.empty();
+
+    // GH#11119: If we find that the settings file doesn't exist, or is empty,
+    // then let's quick delete the state file as well. If the user does have a
+    // state file, and not a settings, then they probably tried to reset their
+    // settings. It might have data in it that was only relevant for a previous
+    // iteration of the settings file. If we don't, we'll load the old state and
+    // ignore all dynamic profiles (for example)!
+    if (firstTimeSetup)
+    {
+        ApplicationState::SharedInstance().Reset();
+    }
+
     const auto settingsStringView = firstTimeSetup ? UserSettingsJson : settingsString;
     auto mustWriteToDisk = firstTimeSetup;